Foot bone density in diabetes may be unaffected by the presence of neuropathy

Despite years of research, the cause of Charcot foot remains poorly understood. A relation between neuropathy and bone density has been suggested as possible explanation. New Australian research investigated the assertion that dense peripheral diabetic polyneuropathy is associated with osteopenia of foot bones.

In a cross-sectional case-control design, the investigators from the University of Newcastle compared two groups with diabetes – those with peripheral neuropathy as determined by standard clinical tests and those without. Groups were matched for age, BMI, type and duration of diabetes, and gender. Foot bone density was determined with computed tomography scanning for each tarsal and metatarsal bone and compared between these two groups. The study did not find any consistent relationship between the presence of neuropathy and poor foot bone density. Furthermore, the study found no association between cardiac autonomic function, small fibre sensory neuropathy or post-occlusive reactive hyperaemia and foot bone density.

This is further evidence in refutation of the assertion that nerve deficits are linked with poor foot bone density that is often cited as an underlying cause of Charcot foot. The primary limitations of the study include the sample size (23 in each group), the method of determining presence or absence of neuropathy which may have led to some of the control group having some degree of neuropathy, and the method of bone density ascertainment being restricted to assessment in Hounsfield units. Despite these limitations, this study challenges a long-held belief about the relationship between neuropathy and foot bone health. The cause of Charcot foot remains an intriguing and so far unsolved puzzle.

This summary has been written by Alex Barwick